Corn: Northern Corn Leaf Blight (Setospaeria turcica)

Pub 812: Field Crop Protection Guide > Chapter 1: Corn > Northern Corn Leaf Blight

Field Crop Protection Guide 2011-2012, Order 2011-2012 publication

Table of Contents

  1. Description
  2. Integrated Pest Management Options
  • azoxystrobin + propiconazole - Quilt
  • propiconazole - Tilt 250 E, Bumper 418 EC
  • prothioconazole - Proline 480 SC
  1. Related links...


Description

The disease appears as long, elliptical (2-15 cm (1-6 in.)) greyish-green or tan streaks. Lesions most often begin on the lower leaves. As the disease develops, individual lesions may join, forming large blighted areas. In some cases the entire leaves may become blighted or "burned." Losses due to northern leaf blight are most severe when the leaves above the ear are infected at or slightly after pollination. The disease is often confused with Stewart's wilt.

Image 1. Northern corn leaf blight showing long elliptical greyish-green or tan streaks.
Image 1. Northern corn leaf blight showing long elliptical greyish-green or tan streaks.

Integrated Pest Management Options

Risk of this disease is on the rise in Ontario. Northern corn leaf blight is not generally a problem in field corn, since good resistance is avaiable in hybrids. Consult with your seed company and the Ontario Corn Committee Hybrid Performance Trials at www.gocorn.net for hybrid selection. Seed corn may need protection. Crop rotation and tillage will reduce inoculum levels in surface residues. In reduced tillage systems, rotation and resistance are necessary. Chemical control is not usually economical in field corn.

 
Active ingredient azoxystrobin + propiconazole
Trade name Quilt
Rate per hectare (product) 0.75-1.0 L per ha
Rate per acre (product) 305-406 mL per ac
PHI* 30
Comments Ground and aerial application. Apply when disease first appears, followed by a second application 14 days after, if environmental conditions are favourable for disease development. Do not apply to field corn or field corn grown for seed after brown silk. Maximum 2 applications/yr.

 

 
Active ingredient propiconazole
Trade name Tilt 250 E
Rate per hectare (product) 250-500 mL per ha
Rate per acre (product) 100-200 mL per ac
PHI* 14
Comments Ground and aerial application. Apply when rust pustules first appear. Under severe disease pressure, a second application 14 days later may be necessary. Only in seed corn, under severe disease pressure can a third application be made 14 days later. Can be tank-mixed with Ripcord or Matador insecticide for insect control.

 

 
Active ingredient propiconazole
Trade name Bumper 418 EC
Rate per hectare (product) 150-300 mL per ha
Rate per acre (product) 60-121 mL per ac
PHI* 14
Comments Ground and aerial application. Apply when rust pustules first appear. Under severe disease pressure, a second application 14 days later may be necessary. Only in seed corn, under severe disease pressure can a third application be made 14 days later. Can be tank-mixed with Ripcord or Matador insecticide for insect control.

 

 
Active ingredient prothioconazole
Trade name Proline 480 SC
Rate per hectare (product) 420 mL per ha
Rate per acre (product) 170 mL per ac
PHI* 14
Comments Ground application only. Maximum 1 application/yr. 24-hr re-entry period.

 

Related links...

 


For more information:
Toll Free: 1-877-424-1300
Local: (519) 826-4047
E-mail: ag.info.omafra@ontario.ca
Author: OMAFRA Staff
Creation Date: 2 May 2011
Last Reviewed: 10 May 2011